1. Field of the Invention
This invention is in the field of water filters and more specifically, filters for aquarium tanks.
2. Description of the Prior Art
A number of prior art devices have been provided for filtering and aerating water within an aquarium tank. The traditional method of aerating water within a tank is to force a stream of air through the water whereas the water is removed from the tank for filtering by an external device. In the U.S. Pat. No. 3,738,491 issued to D. J. Dockery, the gravel at the bottom of the aquarium tank is used to trap waste material and debris so that it can be eliminated by natural decay or by backwashing of the gravel. Another U.S. Pat. No. 3,516,544 issued to W. Sesholtz discloses an aquarium filter having a perforated filter positioned at the bottom of the tank. The more traditional external filter is disclosed in the U.S. Pat. No. 3,554,375 issued to A. H. Willinger whereas U.S. Pat. No. 3,759,223 issued to R. A. D'Andrea discloses a filter located at the bottom of the tank with the water being drawn from the bottom of the tank through the filter. A more complex filter is disclosed in U.S. Pat. No. 3,774,766 issued to H. E. Brock which has a plurality of compartments through which the water flows. Another multiple compartment device is disclosed in U.S. Pat. No. 3,247,826 issued to R. G. Girard.